The textile industry is one of the oldest in the world. The oldest known textiles, which date back to about 5,000 B.C., are scraps of linen cloth found in Egyptian caves. The industry was primarily a family and domestic one until the early part of the 1500s when the first factory system was established. However, it was not until the XVIII century that power machines for weaving or spinning were invented, machines that replaced manual power (Neefus, J. D. “Textile Industrial Processes,” in Aspects of Industrial Hygiene Plant Operations, Volume 1, 1982).
The method for manufacturing textile products comprises a large number of unit operations using several raw materials, such as cotton, wool, synthetic fibers, or mixtures thereof. The environmental impact of their liquid effluents varies by the wide variety of raw materials, reagents and methods of production. In the effluents, there can be found salts, starch, peroxides, EDTA, surfactants, enzymes, dyes, metals and other organic compounds of different structures that come from several steps of the overall process (Mansilla, H D, et al., “Tratamiento de residuos líquidos de la industria de celulosa y textil” en Eliminación de Contaminación por Fotocatálisis Heterogena, CYTED, 2001)
In general, discharge watercourses come mainly from degumming (15%), scouring and mercerizating (20%), and from bleaching, dyeing and washing (65%). The greatest contribution of the organic load comes from the degumming step, which provides about 50% of the BOD (O'Neill C., et al., J. Chem. Technol. Biotechnol., 1999).
The amount of water used in textile processes considerably changes depending on the specific process and equipment used by the plant. For example, around 100 and 150 liters of water per kilogram of product is used when dyeing with disperse dyes. When dyeing with reactive dyes, the range varies from 125 to 170 liters per kilogram of product (EPA Profile of the Textile Industry, 1997).
The textile industry does not release large quantities of metals; however, even small involved concentrations may produce accumulations in the tissues of aquatic animals. The high content of nitrogen in the discharge can increase the population of fish and seaweed, and deplete the oxygen dissolved in the water at a long-term period. Textile dyes last long in the environment, and classic elimination methods are not useful due to the fact that partial oxidations or reductions may generate highly toxic products (O'Neill C., et al., J. Chem. Technol. Biotechnol., 1999).
Most of colorants currently used in the textile industry are synthetic, water-soluble, highly resistant to chemical agents and poorly biodegradable. About 60% of colorants that are being used comprise in their structure highly reactive azo, anthraquinone or phthalocyanine groups that form an ether type union with the fiber (Mansilla, H D, et al., “Tratamiento de residuos líquidos de la industria de celulosa y textil” en Eliminación de Contaminación por Fotocatálisis Heterogena, CYTED, 2001).
Several physicochemical techniques are used for removal of synthetic dyes, such as coagulation and flocculation combined with filtration and flotation, precipitation-flocculation with Fe(II)/Ca (OH)2, ozone oxidation, membrane filtration and reverse osmosis, among others, all of which produce effluents with good quality (Fernandez, J. A., et al., Rev. Colomb. Biotechnol. 2009).
However, most of these techniques are highly expensive, reason why some other alternative treatments are sought, such as the use of biological treatments, which are usually cheaper due to their inexpensive raw materials, and can be worked with resources that in many cases turn out to be wastes from other activities (Moeller, G., Garzón, M. Anuario Lmta, 2003).
Most of the microorganisms (m.o) used in the bioremediation of contaminated effluents are wood-decay fungi, a group of heterogeneous m.o having in common the ability to degrade lignin and other components from the trees, such as cellulose. They produce extracellular enzymes that oxidize phenolic compounds. Among the characterized enzymes are laccases, manganese peroxidases, lignin peroxidases and peroxide-generating enzymes. The activity of these m.o on colorants is based on the non-specificity of the enzyme system for depolymerizing and mineralizing lignin (Moeller, G., Garzon, M. Anuario Lmta, 2003). It has been seen that in most fungi the ligninolysis occurs during the second metabolism, i.e., during nutrient limitation, allowing the fungi to only synthesize and secrete ligninolytic agents starting polymer degradation (Sathiya, P., et al., Rev. Iberoamericana, 2006).
Immobilization of m.o on organic or inorganic supports for the treatment of urban and industrial wastewater has shown good results in terms of color removal, phenols and chlorinated compounds, showing advantages such as increased metabolic activity of the immobilized m.o, easy recovery of m.o and biocarriers, contact surface, persistence within the system, increased resistance to toxicity, and environmental changes.
In the case of filamentous microorganisms, immobilization can be taken for the production of polysaccharides that act as glue within the attachment with the support or by adsorption to supports with high porosity that allow the filaments to enter into the support and to keep retained by physical, hydrophobic, Van der Waals, hydrogen bonding, ligand exchange, ion exchange or chemisorption interactions (Herrera, A., Rosas, J. Pontificia Universidad Javeriana, 2003).
The availability, cost and efficiency in mass retention should be taken into account among the criteria for choosing the immobilization support. Pita from sisal leaves (Furcraea spp.) is the Colombian natural fiber par excellence, which originates in the tropical America, the Andean region of Colombia and Venezuela. Sisal is cultivated in Colombia, and has been extracted since time immemorial for the manufacture of hammocks, nets, ropes, sandals, jiqueras (bags), sacks and packsaddles (MAVT, MINAGRICULTURA, DEPTO PLANEACIÓN, Republic of Colombia, 2006).
The sisal is a perennial plant that reaches up to 5 meters high, and its stalk, which is succulent, fibrous and with several floral scars, reaches up to 40 cm in diameter. Its leaves or succulent green fleshy leaves and with parallel nervations reach up to 2.5 meters long; they look like rigid lances (lanceolate), and also have many hooked thorns in their margins, which become red when water is scarce. Its succulent flowers have about 3 cm in diameter, are fragrant, have 3 petals and 3 greenish white sepals, and its stamens are yellow. They are arranged in straight and branched inflorescences (scape or century plant) that can reach up to 15 meters high. Its fruits are about 2 cm in diameter and its seeds germinate in the same plant, propagules fall to the ground already formed, reason why it is considered as a viviparous plant (Mahecha et al., 2004. Available at Red Nacional de Jardines Botánicos).
The sisal leaf is composed by water (85%), cellulose (6%), protein, saponins and sapogenins (8%), and minerals (1%). The extracted sisal fiber represents a maximum of 4% of the total weight of the leaf, and its main structure corresponds to cellulose, lignin and pentosans. Each filament consists of elementary fibrils bonded together by lignin, and the ends of the fibrils are superposed to form multicellular filaments along the leaf, which form the sisal fiber (MAVT, MINAGRICULTURA, DEPTO PLANEACIÓN, Republic of Colombia, 2006).
In the field of biological treatment of industrial waste with immobilized m.o on cellulose supports, Patent WO03/035561 teaches a method for treatment of dyes and colorants of the textile industry with different physicochemical characteristics. The first step of the process involves pretreating the residues with ozone or adsorption of the waste on biodegradable supports, membrane filtration (micro or nanofiltration), osmose, electrolytic processes, sodium borohydride process, electrolysis, electrochemical oxidation and electrodialysis, among others. Pretreatment is performed for 10 minutes to 72 hours, and when performed with ozone it may last 1 to 3 hours, in the case of a discoloration effect.
The second step of the treatment involves contacting the wastewater with wood-decay fungi, specifically with Clitocybuladusenii, Trichodermaharanium and Trichodermalongibrachiatum species. Fungi is cultivated at about 20 and 45° C. and at a pH 4 to 9, nitrogen, carbon and mineral salts sources are used for their growth. During treatment, wood-decay fungi can be added to the pretreated waters in polymer matrices and encapsulated form.
The polymers comprising such matrices are made from biodegradable, natural and non-toxic materials and are selected from the group consisting of alginates, maltodextrins, corn starch, kappa carrageenan and iota carrageenan salts. Other polymers that may be useful are cellulose or polypropylene derivatives on which the culture is inoculated in order to continue treatment. These biological substrates of cellulosic materials such as polypropylene achieve immobilizing the culture because they form a mesh or woven web that facilitates the growth of the fungi.
The WO03/035561 patent also teaches that it can be possible to use hydrolytic enzymes, cellulolytic enzymes and ligninolytic enzymes activity for the removal of pollutants. The organisms used for the treatment corresponds to lignicolous wood-decay fungi chosen from the group consisting of: fungi of the genus PleurotusyPhanerochaete. 
The WO94/25190 teaches a method treating solid materials with organic contaminants comprising intimately mixing the contaminated material with an actively-growing fungal biomass in a ratio of 1:1 to 10:1 under aerobic conditions, wherein the biomass comprises a lignocellulosic substrate throughout which are distributed spores or propagules of a lignolytic fungus of the genus Phanerochaete. Additionally, biomass includes a mixture of bacteria which act to maintain the temperature of the mixture at 5 to 40° C., and bacteria or enzymes which utilize as a substrate the degradation products of the contaminants. Aeration and moisture of the mix are controlled resulting in the production of free radicals and cleaving of complex contaminant structures such as chlorophenols and polyaromatic hydrocarbons. At the end of the process, the support material is degraded and fungi introduced decline in numbers due to competition from the natural population.
The US2008264858 patent discloses a burlap bags or sacks for the treatment of agricultural and urban wastewater, comprising: (i) a filling with biodegradable material selected from woodchips, sawdust, straw, paper, cardboard, agricultural waste products, wood wastes, composts and combinations thereof, inoculated with a saprophytic fungus selected from the group consisting of Pleurotus ostreatus, Pleurotus pulmonarius, Pleurotus dryinus, Pleurotus tuberregium, Piptoporus betulinus, Fomitopsis pinicola, Fomitopsis officinalis, Trametes versicolor, Hypsizygus ulmarius, Ganoderma lucidum, Ganoderma applanatum, Ganoderma curtisii, Ganoderma oregonense and Ganoderma tsugae; (ii) seeds of grasses, bushes, trees, or hyperaccumulator plants and combinations thereof.
The CN101549936 patent discloses a method for wastewater treatment in which the effluent pH is initially adjust between 4 and 5.5, and inoculated supports are added with a white-rot fungi (Phanerochaetechrysosporium), and the temperature is adjusted between 35 and 60° C. with constant shaking speed of 170 rpm. The m.o growth is performed in a potato flour leaching culture medium (potato 4 g/100 ml, glucose 2 g/100 ml, KH2PO4: 0.3 g/100 ml, MgSO4: 0.15 g/100 ml; and yeast medium components (glucose 0.5 g/100 ml, KH2PO4: 0.1 g/100 ml, (NH4)2SO4: 0.1 g/100 ml, MgSO4*7H2O 0.05 g/100 ml, yeast extract 0.02 g/100 ml), pH 5.0-6.0, previously sterilized at 121° C. for 20 min and cooled to a temperature between 28 and 34° C. (0.05 g ratio of fungus per 250 mL of culture medium, constant shaking for 3 days).
The inoculated m.o is a support comprising: (i) a corn core pre-treated with NaOH 3%, H2S04 3% and industrial alcohol 75%, oven dried at 50° C. and sterilized at 121° C. for 15 min, and (ii) a coating around the core consisting of copper mesh and nylon thread, where the support comprises 0.3 g of core and a coating of about 0.2 and 1.8 g of copper mesh and 0.2 to 1.1 of nylon thread.
The FR2772623 patent discloses a method for treating recalcitrant contaminants such as soil aromatic polycyclic hydrocarbons, comprising the steps of: (i) pasteurizing a lignified organic support (16 h cycles at about 65 and 85° C.) selected from wood chips, bark or corn cobs; (ii) inoculating the organic support with a fungus of the Polypore family, preferably Coriolusversicolor, which is in the form of: (a) a solution of spores and/or mycelial fragments suspended in a liquid medium, (b) mycelium previously developed in a liquid medium, (c) mycelium previously set on a solid support (gelled solid medium or sterilized cereal grains); (Iii) incubating the inoculated support in suitable conditions for fungal growth; and (iv) introducing the inoculated support in contaminated soils to be treated in a ratio between 1 and 50%, preferably between 5 and 20% (wt %).
The CN1544610 patent teaches a method for degradating stalks comprising mixing the waste material with a liquid culture containing lactobacillus, Streptococcusfaecali and Candidautilis in 1 to 20000 proportions (inoculum: substrate) with addition of 0.9% NaCI at 25-30° C. for 7 to 10 days. Subsequently, it is mixed with wood-decay fungi (PhanerochaeteyloPleurotus) and fermented at 25-30° C. until degradation of the plant material.
Moreover, the DE10125365 patent teaches the combination of fungi with monooxygenase/dioxygenase activity (Trametesversicolor; Pleurotusostreatus or Phanerochaetechrysosporium) and Zygomycotina fungi with glutathione-S-transferase activity (Cephalosporium, Penicillium, TrichodermayMucor) for the degradation of xenobiotics, wherein the most efficient bioremediation of contaminated soils and water was the combination of Phanerochaetechrysosporiumy Mucorhiemalis f.
Notwithstanding the foregoing, there is still the need to develop specific combinations of microorganisms like wood-decay fungi for treating water with high COD and BOD values, contaminated with azo, triphenylmethane, aniline or anthraquinone colorants in mixes that comprise additives and heavy metals—for example wastewater from the textile industry, plastic arts industries and industries that generate contaminated water with heavy metals, among others—, conditions under which individual treatments with fungal strains do not generate efficient results.